Canister



June l, i948. w. E. GROSS 2,442,356

CANISTER Filed April` 19, 1944 Patented June 1, 1948 agata eANrsTEn William Gross, ,lonraMd- Application April 1.9., 1944 Serialle- 5.31375 lcresfzssl (Granted, underl the act of, lttlarchy 3 1883, as

amended April. 30, 192.8; 370 0, G- 75.7)

4 Claims.

The invention described herein may be manufatured and used by or for theV Government, vfor governmental purposes, withoutthe payment to me of any royalty thereon.

This invention is concerned with means for diversifying and amplifying the` protective action of gas mask canister-s and the like.v More particularly, it has the object of providing for useand small to not hamper the wearer or give excessive breathing resistance. For these rea-.

sons the military gas mask canister does not A have 'adequate filling to adapt it for protection against high concentrations of war gas, e. g., concentrations above 1%, or against certain toxic gases which are less frequently expected to` be encountered, such as carbon monoxide.

Although there are all-purpose canisters designed to'provide protection against a large vae riety of toxic gases, these have the limitationof breaking down in a short time on account of the limited amounts of specic fillings they contain for absorbing the different gases.

Accordingly, it is an object-of this invention to provide an auxiliary canister adapted to be readily attached to a standard canister inan emergency for increasingprotective action and means for effecting a quick and eflicient seal,

In a more specific sense, a further object of this invention is to provide an auxiliary canister designed to give a quick-acting, air-tight seal that permits `attachment or detachment in the field without the use of adhesives, tapes, tools, etc., and which can be manipulated promptly into a proper position.

A further object is to provide a multi-purpose canister made up of sections which are readily put together to form a puration train suited for the air purification required; also, to provide auxiliary sections constructed in a simplified form so that they are light in weight, give low air resistance, are readily assembled and easily ref canister so. that it telescopes readily over an inlet end portion of another canister or section and securely wedges a sealing member of rubber or similar rubbery or compressible material, such as synthetic rubber or elastomers.

For a more detailed description, reference is made to the accompanying drawings, wherein:

Figurev l shows a sectioned side View of one type ofauxiliary canister assembled in combination with a standard type cylindrical canister;

Figure 2 sh'ows an inlet end View of the auxiliary canister illustrated in Figure l;

Figure 3 vis an enlarged fragmentary crosssection view of the auxiliary canister, along line 3T3 in Figure l; and

Figure 4 .shows a sectioned side View of a second type of auxiliary or sectional canister, the View being reducedin scale.

Referring to the vdrawings and particularly to Figures 1, Zand 3, I represents the bottom part of a standard military-type canister having a common kind of filling, such as activated charcoal, whetlerite, or soda lime mixed with charcoal, for removing war gas contaminants from air which enters the canisterthrough a valved inlet Z in a doublefseamecl bottom 3.

The auxiliary canister body or casing 'iV has an open end extension telescoped over the bottom DQrtion of thecanister I, as shown in Figure l, with' the curled rim or lip 5 flexed a short distancefrom the` outer side wall of canister I. A rubber sealing ring 6 is wedged and held firmly between the outer side wall of canister I and the outwardly beaded groove or indentation 'i in the auxiliary. canister body 4 near rim 5 The double seam 3. of canister I rests against an inwardly indented circumferential bead 8 in canister body 4.-

The circumferential groove at the back of theV inwardly indented bead 8 is spaced a further distance away from the .rim 5 than is the outward bead I and is located so that a perforated retaining plater; is held rmly against the iilling Within the auxiliary canister body 4, and `away fromthe bottom inlet valve 2 of canister l. The inward bead 8, accordingly, may be considered tohave several functions. It xes the distance oi insertion and acts as a support for the perforated retaining plate S.

The perforatedrretaining plate 9 is preferably dished inwardly tor press rmly against the fillinginaterial withinthe auxiliary canister.

For the purpose of illustration, the filling shown in the auxiliary canister is intended for Qlimlftm 951139.11 mOllOXde from ar- Carbon monoxide is not removed by the ordinary or standard military-type gas mask canister. It is a very insidious toxic gas which has no odor. It is present in automobile exhaust gases, in mineexplosion gases, in burning buildings, and in gases from burning smokeless powder.

'I'he filling shown for eliminating carbon monoxide includes a layer IU of caustic pumice, an intermediate layer II of a low-temperature carbon monoxide catalyst, such as hopcalite, and another layer I2 of caustic pumice. I'he caustic pumice is a granular preparation of caustic soda and pumice capable of retaining a number of acid gases and absorbing water vapor which tends to inhibit the action of the hopcalite. Hopcalite is a known specially prepared mixture of manganese dioxide and copper oxide in granular form which converts carbon monoxide into innocuous carbon dioxide. Wire screen separators I3 and I4 are placed between the layers of caustic pumice and the granular catalyst layer II.

The bottom I 5 of the auxiliary canister is perforated as shown in Figure 2 to act as an air inlet. After passing through the perforations, the air flows axially rst through layer I2 of caustic pumice, then through layer I I of carbon monom'de catalyst, then through layer I0 and, with carbon monoxide eliminated, into the inlet of the military-type canister, whence it is inhaled into the gas mask directly or through a hose.

To attach the auxiliary canister to the gas mask canister, the following procedure is followed: (a) the rubber ring 6 is placed on the gas mask canister body I at one point and held against the double seam with the left thumb, the rest of the ring is then laid (without twisting) over the double seam and onto the canister much in the same way as an automobile tire is placed on its rim, taking care to have the ring in contact with the double seam 3 when finished; (b) with the auxiliary canister 4 resting against a solid flat surface, the angle of which is immaterial, or with the canister I and the auxliary canister 4 held in each hand, the gas mask canister I is pushed into the open end of the auxiliary canister 4 until the rubber ring 6 on the gas mask canister contacts the rim 5, then rolls between body I and the inner wall of canister 4 and snaps int-o the groove made by outward bead 1. The rubber ring I thus becomes wedged in place, and the canister I may be pushed up against the inward bead 8 which serves as a stop.

The modied form of auxiliary or sectional canister shown in Figure 4 has a construction which is similar to that of the auxiliary canister illustrated in Figure 1 but has a detachable inlet cover I6 which can be readily removed from the canister body 4 so that the filling can be put in place after the canister body is formed and can be removed for renewal. The cover IS may be secured to the canister body by a friction t, threaded engagement, bead and groove engagement, or a similar manner, and is preferably dished inwardly to press against the lling. Another feature of this modied form of auxiliary canister is in the use of layers I1 and I8 of resilient` fibrous, inorganic material on -both sides of granular adsorptive or absorptive material I9.

A resilient brous, inorganic material, such as rock wool, advantageously serves to compress and hold the granular material in place, thus preventing channeling, even when the canister is subjected to rough handling. Preferably, the pads of fibrous filter material are cut oversize. If proper binding agents are used, the resilient brous Inaagainst high concentrations of hydrocyanic acid,

the intermediate granular material in the auxiliary canister may be made up of a first layer of charcoal impregnated with hexamethylenetetramine followed by a layer of caustic pumice and another layer of charcoal impregnated with hexamethylenetetramine. These layers may be held in place by means of fibrous rock wool. Thus, any type of adsorptive and/or absorptive material may be placed in the auxiliary canister for protection against one or more specic toxic gases. Also, in the event a new toxic agent is developed, a new counteracting agent may be provided in auxiliary canisters for quick distribution and use in the eld.

The simplified auxiliary canister requires a minimum use of machinery, of critical material such as steel, and of skilled labor for its production. It readily lends itself to manufacture from non-metallic material, such as plastics; and even if made from metal, a relatively small amount of metal is used.

By virtue of the tough resilient nature of the ltering medium made of a siliceous or inorganic material, such as rock wool, the auxiliary canister containing such a ltering medium does not require the use of separators; thus, the amount of metal is substantially reduced. The cushioning eiect of the resilient filtering medium permits chemical absorbents of low hardness value and high efficiency to be used Without lining during rough usage. Also, with the detachable perforated inlet cover, the canister can be readily assembled, repaired and renewed by unskilled personnel without the need for special vibrating and compacting apparatus. The resilient lter medium gives the air flow an even distribution over the cross-sectional area of the granular layer and thus dispenses with the use of baflles or other internal structure which offers resistance to air ilow.

With the construction shown, the auxiliary canister can be quickly and securely attached to another canister of approximately the same crosssectional dimensions, and an air-tight seal is effected regardless of any small irregularities of the surfaces sealed and regardless of the presence of a double seam at the bottom of the canister telescoped by the auxiliary canister. The attachment can be manipulated promptly and securely by use of the procedure described.

With the type of canister having a detachable bottom inlet and resilient fibrous material to compress the filling, the canister may be salvaged and packed in the eld with air-purifying agents shipped in bulk, thus making a saving in shipping space and in the preservation of the agents during storage and shipment.

Complete engineering tests on canisters constructed in accordance with the present invention proved the canisters to be satisfactory in every way.

The auxiliary canister can be made of convenient size for packing in an hermetically-sealed container which is not opened until the need for protection against a toxic gas like carbon monoxide is judged to be imminent. Thus, the protective value of the canister can be preserved, for otherwise the protective value may tend to be destroyed by exposure to moisture, particularly if proper functioning of the chemical adsorbents depends upon low moisture content. A satisfactory container for storing the canister is constructed like a colee can, having a circumferential tear strip and provided with a key for opening.

With the hopcalite catalyst, which is inhibited by water vapor, it is also desirable to have a layer of about 75 cc. of silica gel and a layer of about 100 cc. of eharcalite (activated charcoal impregnated with about 30-45% calcium chloride) precede the catalyst, 110 cc., with screen separators between the layers and to have a rock wool pad next to the catalyst in the order named. This type of canister, after preservation in an hermetically-sealed container, is very effective for restraining carbon monoxide.

In my co-pending application, Serial No. 519,597, led January 25, 1944, I have described and claimed the use of resilient rock wool in airpurifying canisters more generally.

It is to be understood that the invention is not limited to the details of construction herewith shown by way of illustration, since modiiications come within the spirit and scope of the invention.

I claim:

1. In an auxiliary air-purifying canister a body having an air inlet and outlet, an air-purifying lling disposed in an axial path of air flow from the inlet to the outlet in said body, a perforated detachable inlet cover fixed to the body at the inlet, a side wall of said body surrounding said lling, an inwardly indented bead in said wall, and a perforated retaining plate dished inwardly and held by said bead firmly against the lling.

2. In an auxiliary air-purifying canister a cylindrical side wall, an outlet opening substantially in registration with the inner surface of the cylindrical side wall, an inwardly indented bead in the periphery of said side wall, a perforated retaining plate resting against said bead and pressing against a filling comprising a granular air-purifying material and pad of brous rock wool.

3. In an auxiliary gas mask canister adapted for quick and secure attachment to a standard air-purifying canister connected to a gas mask, a canister body shaped to be partly telescoped at one end over a bottom inlet portion of a standard canister, a curled rim at the telescoping end of said body, a perforated inlet cover at an inlet end of said body, an outwardly projecting bead in a telescoping portion of said body near the curled rim, an inwardly projecting bead in the wall of said body located further from the curled rim than said outwardly projecting bead, a perforated retainer plate resting against said inwardly projecting bead, and interposed between said retainer plate and the perforated inlet cover a granular air-purifying material sandwiched between pads of resilient rock wool filtering medium.

4. An auxiliary air-purifying canister comprising a body having an airinlet side and an opposite outlet side, an air purifying lling disposed in the axial path of air flow from the inlet to the outlet in said body, the inlet side of the body having an opening substantialliy co-extensive with the cross-sectional area of the body occupied by said air purifying iilling, a perforated removable cover attached to the body over the inlet side opening, said cover pressing against the llng material on the inlet side of said body, a perforated retaining plate pressing against the lling material on the outlet side of said body, an inwardly projecting bead in the wall of said body to serve as a support for said perforated retaining plate, and an outwardly beaded groove in the wall of said body intermediate the outlet end and said inwardly projecting bead.

WILLIAM E. GROSS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 685,818 Close Nov. 5, 1901 837,482 Libert Dec. 4, 1906 853,900 Saunders May 14, 1907 877,309 Emerson Jan, 21, 1908 985,106 Bradshaw Feb. 21, 1911 1,414,194 Levy Apr. 25, 1922 1,422,211 Lamb July 11, 1922 1,485,047 Mueller et al Feb. 26, 1924 1,538,007 Schellin May 19, 1925 1,853,373 Monro Apr. 12, 1932 1,909,635 Rollason May 16, 1933 2,300,912 Dodge Nov 3, 1942 2,327,412 Fink Aug, 24, 1943 2,365,574 McWane Dec. 19, 1944 FOREIGN PATENTS Number Country Date 48,759 Germany Sept. 27, 1889 283,475 Italy Mar. 12, 1931 406,869 Great Britain Mar. 8, 1934 OTHER REFERENCES Katz et al., Bureau of Mines Technical Paper Number 300 (1923), page 4. 

